/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize.info;

import proguard.classfile.*;
import proguard.classfile.visitor.*;

/**
 * This ParameterVisitor delegates all its visits to one of two other ParameterVisitor instances, depending on whether
 * the parameter is used or not.
 *
 * @see ParameterUsageMarker
 * @author Eric Lafortune
 */
public class UsedParameterFilter implements ParameterVisitor {
    private final ParameterVisitor usedParameterVisitor;
    private final ParameterVisitor unusedParameterVisitor;

    /**
     * Creates a new UsedParameterFilter that delegates visits to used parameters to the given parameter visitor.
     */
    public UsedParameterFilter(ParameterVisitor usedParameterVisitor) {
        this(usedParameterVisitor, null);
    }

    /**
     * Creates a new UsedParameterFilter that delegates to one of the two given parameter visitors.
     */
    public UsedParameterFilter(ParameterVisitor usedParameterVisitor, ParameterVisitor unusedParameterVisitor) {
        this.usedParameterVisitor = usedParameterVisitor;
        this.unusedParameterVisitor = unusedParameterVisitor;
    }

    // Implementations for ParameterVisitor.

    public void visitParameter(Clazz clazz, Member member, int parameterIndex, int parameterCount, int parameterOffset,
        int parameterSize, String parameterType, Clazz referencedClass) {
        ParameterVisitor parameterVisitor = ParameterUsageMarker.isParameterUsed((Method)member, parameterOffset)
            ? usedParameterVisitor : unusedParameterVisitor;

        if (parameterVisitor != null) {
            parameterVisitor.visitParameter(clazz, member, parameterIndex, parameterCount, parameterOffset,
                parameterSize, parameterType, referencedClass);
        }
    }
}